Perfluoropolymer materials, in general, are chemically inert and have low surface energies, making them difficult to adhere either to a substrate of the same material or to a substrate of a different material. If the perfluoropolymers comprising these materials also happen to have high melting points, the problem may be even more difficult for reasons referred to below.
In order to improve the adhesion of a high-melting perfluoroplastic, its surface is sometimes chemically modified to introduce functional groups which promote adhesion. Alternatively, the perfluoroplastic may be heated above its high melting point. Especially when high-melting temperatures are involved, however, such processes may be expensive and may lead to undesirable changes in the surface properties of these polymers or to distortion and/or decomposition of the polymer.
Solvents for these polymers have also been used to aid in the process of adhesion, but there are relatively few solvents available for such polymers. Improvements to earlier adhesion processes have been obtained. See, for instance, U.S. Pat. No. 5,237,049. Nevertheless, an improved process that would provide even better adhesion would be highly desirable.